JP4606640B2 - Rotating electric machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotating electrical machine such as a motor, and more particularly to a collar shape of teeth of a stator core that can reduce torque ripple in the entire operation region.
[0002]
[Prior art]
FIG. 7 is a longitudinal sectional view schematically showing a configuration of a conventional magnetic pole concentrated winding motor, and FIG. 8 is an enlarged view showing a main part of a stator core applied to the conventional magnetic pole concentrated winding motor.
7 and 8, the rotor 2 is formed in a cylindrical shape, and the permanent magnets 3 are disposed on the outer peripheral surface thereof at an equiangular pitch in the circumferential direction. As the permanent magnet 3, a ferrite magnet, a neodymium magnet, a samarium cobalt magnet, or the like is used.
[0003]
The stator 5 is formed by laminating magnetic thin plates made of silicon steel plates or the like, and teeth 8 projecting radially inward from the inner peripheral surface of the cylindrical yoke portion 7 are formed on the inner peripheral surface of the yoke portion 7. A stator core 6 formed at a predetermined pitch in the direction and a stator winding 10 wound around the stator core 6 are provided.
Each tooth 8 of the stator core 6 includes a base portion 8a having a predetermined tooth width, and a flange portion 8b protruding from the tip of the base portion 8a on both sides in the circumferential direction. A slot 9 is defined in the stator core 6 by a yoke portion 7 and a tooth 8 adjacent to the yoke portion 7.
Moreover, the stator winding | coil 10 is comprised from the coil | winding 10a for the number of the teeth 8, and the coil | winding 10a is each formed by winding a conductor wire to the base 8a of the one tooth | gear 8 predetermined times. That is, the stator winding 10 is wound around the stator core 6 by the magnetic pole concentrated winding method.
[0004]
The stator 6 configured in this manner is arranged coaxially so as to cover the outer periphery of the rotor 2, and current is passed through the stator winding 10 so that the permanent magnets 3 adjacent in the circumferential direction have opposite polarities. The motor 1 is completed by magnetizing the permanent magnet 3. At this time, the radial front end surface of each tooth 8 is formed on the circular arc surface so that the distance from the outer peripheral surface of the rotor 2 is uniformly spaced, and the air gap 4 having a uniform gap length Lg is formed. It is formed between the rotor 2 and the stator 6.
[0005]
In the conventional motor 1 configured as described above, when the permanent magnet 3 is magnetized, a large amount of short-circuit magnetic flux is generated between the opposite flange portions 8b, and the magnetic flux acting on the permanent magnet 3 of the rotor 2 is reduced. Therefore, there is a problem that the permanent magnet 3 cannot be magnetized efficiently.
In order to solve this problem, by making a hole in a part of the collar part, the magnetic resistance between the opposite collar parts is increased, the short-circuit magnetic flux generated between the collar parts is reduced, and it acts on the permanent magnet. Attempts to increase the magnetic flux have been proposed in, for example, Japanese Patent Laid-Open No. 2000-166133.
[0006]
In the conventional motor as an improvement measure described in Japanese Patent Laid-Open No. 2000-166133, as shown in FIG. 9, the magnetic short-circuit prevention holes 8c are respectively formed at both ends in the circumferential direction of the flange 8b of the teeth 8A. It is installed.
In the conventional motor employing the stator core 6A configured as described above, the magnetic path between the opposing flanges 8b becomes smaller at the portion where the magnetic short-circuit prevention hole 8c is formed, that is, the magnetic resistance is increased, and the gap between the flanges is increased. The short-circuit magnetic flux generated in is reduced. Thereby, since the magnetic flux which acts on a permanent magnet at the time of magnetization of a permanent magnet increases, it is supposed that a permanent magnet can be magnetized now efficiently.
[0007]
[Problems to be solved by the invention]
As described above, the motor as a conventional improvement measure was made for the purpose of improving the magnetizing characteristics of the permanent magnet, and the motor characteristics caused by variations in magnet materials, magnet magnetizing defects, etc. There was no consideration given to the decline of. Therefore, a motor as a conventional improvement measure is insufficient to suppress an increase in torque ripple caused by variations in magnet materials or magnet magnetization failure. In other words, in the vicinity where the opposite flanges 8b face each other, a part that is narrow in the magnetic path is formed, so that generation of a large short-circuit magnetic flux at the time of magnetization can be suppressed using magnetic saturation of the magnetic path. For the magnetic flux generated during use, there is a problem that the short-circuit magnetic path cannot be sufficiently saturated and the magnetic flux cannot be suppressed.
[0008]
Therefore, the inventors have created a manufacturing error such as variations in magnet materials and poor magnetizing in manufacturing the motor, which affects the torque ripple and deteriorates the motor characteristics. In view of the above, in order to suppress an increase in torque ripple caused by a working error during normal use of the motor, a magnetic field analysis was performed focusing on the relationship between the torque ripple and the slot opening width.
[0009]
First, an ideal state with no machining error will be described.
In general, in a permanent magnet motor driven by a three-phase alternating current, a torque ripple having a frequency component of 6n times (n: natural number) the power supply frequency is observed. It is known that the frequency component of the torque ripple has a greater influence as the lower-order component (hereinafter, these lower-order components are referred to as 6f components of the torque ripple). The 6f component of this torque ripple occurs only when power is supplied from the power source, that is, only occurs in a load state.
Here, FIG. 3 shows the results of the magnetic field analysis performed by the inventors on the relationship between La / Lg, torque ripple, and average torque in an ideal motor. La is the slot opening width, and Lg is the air gap length of the air gap 4. The torque ripple shows a 6f component, and it is known that components other than the 6f component are hardly seen. From FIG. 3, it can be seen that in the ideal load state of the motor with no machining error, if the La / Lg is designed to be large, the 6f component of the torque ripple can be reduced and the average torque can be increased. Therefore, in an ideal state, the torque ripple can be reduced by increasing the slot opening width La.
[0010]
Next, an actual state in which a work error occurs will be described. That is, in an actual motor, work errors such as variations in magnet materials and poor magnetization occur.
In this actual motor, in addition to the 6f component of torque ripple, it has been found from the experiments and magnetic field analysis by the inventors that a torque ripple component caused by the above-mentioned work error occurs. The torque ripple component generated by the variation of the magnet is defined by the number of slots of the stator, and the same number of pulsation components as the number of slots per rotation (hereinafter referred to as the torque ripple slot component).
Here, FIG. 4 shows the result of the magnetic field analysis performed by the inventors on the relationship between La / Lg, the 6f component of torque ripple, and the average torque in an actual motor. FIG. 4 shows that in the actual motor load state, the relationship between the 6f component of the torque ripple and the average torque and La / Lg is substantially the same as the ideal load state of the motor with no machining error.
Next, FIG. 5 shows the result of the magnetic field analysis performed by the inventors on the relationship between La / Lg and the torque ripple slot component in an actual motor.
From FIG. 5, it can be seen that the slot component of the torque ripple increases substantially in proportion to La / Lg when the motor is in a no-load state. Therefore, it is desirable to design the slot opening width (La / Lg) to be small in order to reduce torque ripple in an actual motor no-load state.
On the other hand, in an actual motor load state, a torque ripple 6f component is generated in addition to the torque ripple slot component. As can be seen from FIG. 5, the slot component of the torque ripple in the load state does not depend much on La / Lg, but the 6f component of the torque ripple decreases with increasing La / Lg, as can be seen from FIG. There is a tendency. Therefore, in order to reduce torque ripple and increase average torque in an actual motor load state, it is desirable to design La / Lg to be large.
[0011]
Based on the magnetic field analysis result on the relationship between torque ripple and slot opening width, the present inventors have found that in an actual motor (actual machine) in which a working error occurs, the torque ripple in the entire operation region from the no-load state to the loaded state. In order to reduce the load, it is desirable to decrease La / Lg in the no-load state and increase La / Lg in the load state, and the present invention has been invented.
That is, according to the present invention, based on the above points of view, the teeth flange shape is devised so that the slot opening width is substantially different between the no-load state and the load state, and torque ripple is reduced in the entire operation region. An object of the present invention is to provide a rotating electrical machine that can reduce the average torque and increase the average torque.
[0012]
[Means for Solving the Problems]
In the rotating electrical machine according to the present invention, a tooth having a base portion extending radially inward from the inner peripheral surface of the annular yoke portion and a flange portion extending from the tip end portion of the base portion to both sides in the circumferential direction is the yoke portion. A plurality of stator cores arranged in the circumferential direction on the inner peripheral surface of the stator, and a stator having a stator winding wound around the stator core by magnetic pole concentrated winding,
The stator is arranged coaxially so as to have a uniform air gap on the inner peripheral side, a plurality of permanent magnets are arranged on the outer peripheral surface in the circumferential direction, and the permanent magnets adjacent in the circumferential direction have opposite polarities. In a rotating electrical machine having a magnetized rotor,
The heel portion of the tooth extends in the circumferential direction from the base portion, and the heel base portion that is not magnetically saturated in a loaded state, and extends in the circumferential direction from the heel base portion, and has a thin radial thickness with respect to the heel base portion. Yes, and those which are formed in two-step staircase-like shape composed of a flange tip magnetically saturated under load.
[0013]
Further, the stator iron core is configured by laminating magnetic thin plates in the axial direction, and the radial thickness of the heel tip is not less than the thickness of the magnetic thin plate and not more than twice the thickness of the magnetic thin plate. Is formed.
[0014]
In addition, a circumferential gap La between the flange tips adjacent in the circumferential direction, a circumferential gap Lb between the flange bases adjacent in the circumferential direction, and a gap length Lg of the air gap are La <3.7Lg. <Lb relationship.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
1 is a longitudinal sectional view showing a main part of a stator applied to a magnetic pole concentrated winding motor according to Embodiment 1 of the present invention, and FIG. 2 is a front end of a tooth of the magnetic pole concentrated winding motor according to Embodiment 1 of the present invention. It is an enlarged view which shows the circumference of a part. In each figure, the same or corresponding parts as those in the conventional example shown in FIGS. 7 to 9 are designated by the same reference numerals, and the description thereof is omitted.
[0016]
In each figure, the stator 20 is formed by laminating magnetic thin plates made of silicon steel plates or the like in the axial direction, and teeth 23 projecting radially inward from the inner peripheral surface of a cylindrical yoke portion 22 are formed on the yoke portion. A stator core 21 is formed on the inner peripheral surface of 22 at a predetermined pitch in the circumferential direction, and a stator winding 10 wound around the stator core 21 is provided.
Each tooth 23 of the stator core 21 includes a base portion 24 having a predetermined tooth width and a flange portion 25 projecting from both ends of the base portion 24 in the circumferential direction. A slot 26 is defined in the stator core 21 by a yoke portion 22 and two teeth 23 adjacent to each other. Further, the distal end surface in the radial direction of the tooth 23 is formed in an arc surface so that the distance from the outer peripheral surface of the rotor 2 is uniformly spaced. And the collar part 25 is comprised by the staircase shape which consists of the collar base part 25b extended from the base 24 to the circumferential direction both sides, and the collar tip part 25a extended from the collar base part 25b to the circumferential direction both sides. The heel base portion 25b is formed such that its radial thickness gradually decreases from the base portion 24 toward both sides in the circumferential direction, and the heel tip portion 25a has a radial thickness from the heel base portion 25b to both sides in the circumferential direction. It is formed so as to decrease gradually. Further, the radial thickness of the root portion of the heel base portion 25b is Hsb, the radial thickness of the circumferential tip portion of the heel base portion 25b is Hb, the radial thickness of the root portion of the heel tip portion 25a is Hsa, and the heel tip portion. Hsb>Hb>Hsa> Ha when the radial thickness of the circumferential tip of 25a is Ha.
Further, the stator winding 10 is composed of the number of windings 10 a of the teeth 23, and each of the windings 10 a is formed by winding a conductor wire around the base 24 of one tooth 23 a predetermined number of times. That is, the stator winding 10 is wound around the stator core 21 by the magnetic pole concentrated winding method.
Further, the permanent magnets 3 are arranged on the outer periphery of the rotor 2 at an equiangular pitch, and the adjacent permanent magnets 3 are magnetized so as to have opposite polarities.
[0017]
The stator 20 thus configured is arranged coaxially so as to cover the outer periphery of the rotor 2, and the motor 100 is completed. At this time, a uniform air gap 4 is formed between the rotor 2 and the stator 20.
[0018]
In the no-load state of the motor 100 configured as described above, since no current flows through the stator winding 10, the magnetic flux density of the heel tip portion 25a of the heel portion 25 of the tooth 23 does not increase. Thereby, magnetic saturation of the heel tip portion 25a does not occur, and the slot opening width can be regarded as a distance between adjacent heel tip portions 25a (corresponding to La in FIG. 2). That is, La / Lg is reduced, and the slot component of torque ripple caused by a work error can be reduced.
Moreover, in the load state of the motor 100, the magnetic flux which generate | occur | produces when an electric current flows into the stator winding | coil 10 flows into the coffin tip part 25a from the coffin tip part 25a through the coffin base part 25b. Since the magnetic flux density of the heel tip portion 25a is larger than the magnetic flux density of the heel base portion 25b and the magnetic resistance of the heel tip portion 25a is increased, the slot opening width is the distance between the adjacent heel base portions 25b (Lb in FIG. 2). Equivalent). That is, when energized, the slot opening width is equivalently increased. That is, La / Lg is increased, and the 6f component of torque ripple can be reduced.
[0019]
As described above, according to the first embodiment, the flange portion 25 of the tooth 23 is extended to the both sides in the circumferential direction from the flange base portion 25b having a large radial thickness, and compared to the flange base portion 25b. Since it is formed in a stepped shape composed of the heel tip portion 25a having a small radial thickness, the slot opening width is substantially narrowed in the no-load state, and the slot opening width is substantially reduced in the loaded state. To be spread. Therefore, since La / Lg is small in the no-load state and La / Lg (that is, Lb / Lg) is large in the load state, torque ripple can be reduced in the entire operation region from the no-load state to the load state. In addition, a motor capable of increasing the average torque can be realized.
In addition, since the radial thickness of the flange base portion 25b is configured to gradually decrease toward both sides in the circumferential direction, the winding property of the stator winding 10 is improved.
[0020]
Further, the stator core 21 is formed from a magnetic thin plate by press forming a belt-like body in which the yoke portion 22, the teeth 23 and the slots 26 are formed, and after laminating a plurality of the belt-like bodies, the stator core 21 is bent into a cylindrical shape. Produced. Further, an annular body in which the yoke portion 22, the teeth 23, and the slots 26 are formed by press molding from a magnetic thin plate, and a large number of the annular bodies are laminated. Alternatively, a long magnetic thin plate is press-molded to form a long belt-like body in which the yoke portion 22, the teeth 23, and the slot 26 are formed, and the belt-like body is wound in a spiral shape. Therefore, if the radial thickness Ha of the circumferential tip of the heel tip 25a is too thin, the strength of the heel tip 25a is not secured, and bending or bending of the heel tip 25a occurs in the manufacturing process of the stator core. As a result, the manufacturability of the stator core 21 is deteriorated. Therefore, considering the strength of the heel tip 25a, it is desirable that the radial thickness Ha be equal to or greater than the plate thickness (t) of the magnetic thin plate. Thereby, generation | occurrence | production of the bending and the bending of the collar front-end | tip part 25a in the manufacturing process of the stator core 21 is suppressed, and a yield is improved. Further, if the radial thickness Ha of the heel tip portion 25a is set to not more than twice the plate thickness (t) of the magnetic thin plate, a motor having good motor characteristics, that is, a small torque ripple and a large average torque can be realized.
Therefore, it is desirable that the radial thickness Ha of the heel tip portion 25a is t ≦ Ha ≦ 2t. As a result, the manufacturability of the stator core is improved, and the hook tip 25a can be sufficiently magnetically saturated when energized, and a motor with a small torque ripple can be obtained.
[0021]
Here, the relationship between the 6f component and the slot component of torque ripple and La / Lg when a machining error occurs is shown in FIG. In FIG. 6, the relationship between torque ripple at no load and La / Lg is the relationship between the slot component of torque ripple and La / Lg in FIG. 5, and the relationship between torque ripple at load and La / Lg. Is the relationship between the 6f component of torque ripple in FIG. 4 and La / Lg.
From FIG. 6, it can be seen that the 6f component of the torque ripple and the slot component intersect at La / Lg = 3.7. Therefore, in order to reduce the 6f component and the slot component of the torque ripple, it is desirable that La / Lg <3.7 in the no-load state and Lb / Lg> 3.7 in the loaded state. That is, by setting La <3.7Lg <Lb, it is possible to achieve both reduction of torque ripple and improvement of motor efficiency (improvement of DC torque for the same current) in the entire operation range.
[0022]
In the first embodiment, the radial thickness of the root portion of the heel base portion 25b is Hsb, the radial thickness of the circumferential tip portion of the heel base portion 25b is Hb, and the radial thickness of the root portion of the heel tip portion 25a. Hsb>Hb>Hsa> Ha, where Hsa is the thickness and Hs is the radial thickness of the circumferential tip of the collar tip 25a, but the collar shape is Hsb = Hb, Hsa = Ha, Hb> Ha may be formed.
In the first embodiment, the heel tip 25a is formed so that the radial thickness gradually decreases from the heel base 25b to both sides in the circumferential direction. However, the heel tip 25a has a radial thickness. The same effect can be obtained by forming the ridge so as to gradually increase from the flange base 25b to both sides in the circumferential direction.
Furthermore, in Embodiment 1 described above, it is described as being applied to a motor, but the present invention is not limited to a motor, and the same effect can be obtained when applied to a rotating electrical machine such as an AC generator. can get.
In the first embodiment, an example in which the gap length Lg of the air gap is uniform has been described. However, for example, even when a bowl-shaped magnet is attached to the rotor surface, the minimum gap length is provided. If the value is defined as Lg, the same effect can be obtained.
[0023]
【The invention's effect】
Since this invention is comprised as mentioned above, there exists an effect as described below.
[0024]
According to the present invention, the teeth having the base portion extending radially inward from the inner peripheral surface of the annular yoke portion and the flange portions extending from the tip end portion of the base portion to both sides in the circumferential direction are provided inside the yoke portion. A stator core having a plurality of circumferentially disposed circumferential surfaces, and a stator having a stator winding wound around the stator core by concentrated magnetic poles;
The stator is coaxially arranged so as to have an air gap on the inner peripheral side, a plurality of permanent magnets are arranged on the outer peripheral surface in the circumferential direction, and the permanent magnets adjacent in the circumferential direction are magnetized in opposite polarities. In a rotating electrical machine having a rotor that is
The heel portion of the teeth includes a heel base portion extending in the circumferential direction from the base portion, and a heel tip portion extending in the circumferential direction from the heel base portion and having a thin radial thickness with respect to the heel base portion. Therefore, a rotating electrical machine that can reduce torque ripple in the entire operation region can be obtained.
[0025]
Further, the stator iron core is configured by laminating magnetic thin plates in the axial direction, and the radial thickness of the heel tip is not less than the thickness of the magnetic thin plate and not more than twice the thickness of the magnetic thin plate. Since it is formed, the yield of the stator core is improved, and the tip of the heel can be sufficiently magnetically saturated when energized, and the torque ripple can be reduced.
[0026]
In addition, a circumferential gap La between the flange tips adjacent in the circumferential direction, a circumferential gap Lb between the flange bases adjacent in the circumferential direction, and a gap length Lg of the air gap are La <3.7Lg. Since <Lb, the torque ripple can be reliably reduced in the entire operation range.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a main part of a stator applied to a magnetic pole concentrated winding motor according to Embodiment 1 of the present invention.
FIG. 2 is an enlarged view showing the periphery of a tooth tip portion of the magnetic pole concentrated winding motor according to Embodiment 1 of the present invention;
FIG. 3 is a diagram showing a relationship between La / Lg, 6f component of torque ripple, and average torque in a magnetic pole concentrated winding motor with no machining error.
FIG. 4 is a diagram showing a relationship between La / Lg, a 6f component of torque ripple, and an average torque in a magnetic pole concentrated winding motor having a machining error.
FIG. 5 is a diagram showing a relationship between La / Lg and a torque ripple slot component in a magnetic pole concentrated winding motor having a machining error.
FIG. 6 is a diagram showing the relationship between La / Lg, torque ripple 6f component, and slot component in a magnetic pole concentrated winding motor with a machining error.
FIG. 7 is a longitudinal sectional view schematically showing a configuration of a conventional magnetic pole concentrated winding motor.
FIG. 8 is an enlarged view showing a main part of a stator core applied to a conventional magnetic pole concentrated winding motor.
FIG. 9 is an enlarged view showing a main part of a stator core applied to a conventional magnetic pole concentrated winding motor as an improvement measure.
[Explanation of symbols]
2 Rotor, 3 Permanent magnet, 4 Air gap, 10 Stator winding, 20 Stator, 21 Stator iron core, 22 Yoke part, 23 teeth, 24 base part, 25 collar part, 25a collar tip part, 25b collar base part, 100 Motor (rotary electric machine).

Claims (3)

A tooth having a base portion extending radially inward from the inner peripheral surface of the annular yoke portion and a flange portion extending on both sides in the circumferential direction from the tip end portion of the base portion is provided circumferentially on the inner peripheral surface of the yoke portion. A plurality of stator cores, and a stator having a stator winding wound around the stator core with magnetic pole concentrated windings;
The stator is arranged coaxially so as to have a uniform air gap on the inner peripheral side, a plurality of permanent magnets are arranged on the outer peripheral surface in the circumferential direction, and the permanent magnets adjacent in the circumferential direction have opposite polarities. In a rotating electrical machine having a magnetized rotor,
The heel portion of the tooth extends in the circumferential direction from the base portion, and the heel base portion that is not magnetically saturated in a loaded state, and extends in the circumferential direction from the heel base portion, and has a thin radial thickness with respect to the heel base portion. Yes, and the rotary electric machine, characterized in that it is formed in two-step staircase-like shape composed of a flange tip magnetically saturated under load.   The stator iron core is configured by laminating magnetic thin plates in the axial direction, and the radial thickness of the tip of the flange is formed to be equal to or greater than the thickness of the magnetic thin plate and not more than twice the thickness of the magnetic thin plate. The rotating electrical machine according to claim 1, wherein:   A circumferential gap La between the flange tips adjacent in the circumferential direction, a circumferential gap Lb between the flange bases adjacent in the circumferential direction, and a gap length Lg of the air gap are La <3.7Lg <Lb. The rotating electrical machine according to claim 1 or 2, wherein the relation is

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